Although what you say is true, keep in mind that some things you may want to do might not be available in some countries, especially poor ones.
For example, I grew up in a certain country, and as an early adult I wanted to put a game I was making on kickstarter. After a bit of research, I found out kickstarter doesn’t support my country (not sure if that has changed now).
Apart from that, yes living in a country with low cost of leaving would be better financially (assuming you plan to survive with game dev). But that comes with living in a poorer place, where the way of living might be not as comfortable as the more expensive places.
Assuming one is an indie game dev with a very small team, or alone, there certainly is no reason to live in an area like Silicon Valley, unless you want to make new connections.